NEW SOFTWARE, NEW LEADER: Microsoft CEO Steve Ballmer ushered out Steve Sinofsky, the head of the company's Windows division, in a surprise move announced late Monday. The shake-up came less than three weeks after Ballmer and Sinofsky unveiled Windows 8, a dramatic overhaul of Microsoft Corp.'s lucrative operating system.

POWER STRUGGLE: No definitive reason was given for Sinofsky, but analyst believe he may have been resisting Ballmer's attempts to weave Microsoft's products more closely together so the technology is easily accessible whenever and wherever people want to work, play and communicate.

WALL STREET WORRIES: Microsoft's stock fell 3 percent Tuesday.